School of Materials Science and Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States.
Department of Applied Physics, Chongqing University , Chongqing 400044, China.
ACS Nano. 2016 Apr 26;10(4):4797-805. doi: 10.1021/acsnano.6b01569. Epub 2016 Apr 18.
Electromagnetic generators (EMGs) and triboelectric nanogenerators (TENGs) are the two most powerful approaches for harvesting ambient mechanical energy, but the effectiveness of each depends on the triggering frequency. Here, after systematically comparing the performances of EMGs and TENGs under low-frequency motion (<5 Hz), we demonstrated that the output performance of EMGs is proportional to the square of the frequency, while that of TENGs is approximately in proportion to the frequency. Therefore, the TENG has a much better performance than that of the EMG at low frequency (typically 0.1-3 Hz). Importantly, the extremely small output voltage of the EMG at low frequency makes it almost inapplicable to drive any electronic unit that requires a certain threshold voltage (∼0.2-4 V), so that most of the harvested energy is wasted. In contrast, a TENG has an output voltage that is usually high enough (>10-100 V) and independent of frequency so that most of the generated power can be effectively used to power the devices. Furthermore, a TENG also has advantages of light weight, low cost, and easy scale up through advanced structure designs. All these merits verify the possible killer application of a TENG for harvesting energy at low frequency from motions such as human motions for powering small electronics and possibly ocean waves for large-scale blue energy.
电磁发电机（EMG）和摩擦电纳米发电机（TENG）是两种最强大的采集环境机械能的方法，但每种方法的有效性都取决于触发频率。在这里，我们在低频运动（<5 Hz）下系统地比较了 EMG 和 TENG 的性能后，证明了 EMG 的输出性能与频率的平方成正比，而 TENG 的输出性能与频率大致成比例。因此，TENG 在低频（通常为 0.1-3 Hz）下的性能比 EMG 要好得多。重要的是，EMG 在低频时输出电压极低，几乎无法驱动任何需要一定阈值电压（∼0.2-4 V）的电子元件，因此大部分采集到的能量都被浪费了。相比之下，TENG 的输出电压通常足够高（>10-100 V）且不依赖于频率，因此大部分产生的功率都可以有效地用于为设备供电。此外，TENG 还具有重量轻、成本低以及通过先进的结构设计易于扩展的优点。所有这些优点都验证了 TENG 可能在低频下从人体运动等获取能量的杀手级应用，为小型电子设备供电，甚至可能为大规模的蓝色能源获取海浪能量。
